Tallow color stabilization



TALLCW COLOR STABILIZATION Rex J. ims, La Grange, and De v itte Nelson,Elmhurst, iii, assignors to Swift & Company, Chicago, 111., acorporation of Illinois No Drawing. Application March 20, 1953, SerialNo. 343,758

3 Claims. (Cl. 260--398.5)

The present invention relates to color stabilization of fats. Morespecifically, "the invention is directed to the stabilization ofdecolorized tallow against color reversion.

One of the major problems in the production of tallow is the control ofcolor reversion tendencies exhibited by ecolorized tallow. In thedecolorization of tallow the tallow is normally treated with propane toremove color bodies. This treatment provides a desirable product withrespect to color but does not provide a color-stable product. Thedecolorized tallow often exhibits color reversion tendencies and beforeit reaches the consumer it is too dark for use. Under storage conditionsthe tallow is normally subjected to elevated temperatures which arerequired to maintain the tallow in a fluidized condition. Tallow thusstored exhibits greater color reversion tendencies and the rate ofdarkening increases with increases in temperature.

Propane-decolorized, inedible tallow will sometimes darken to a colorabove soap manufacturersspecifications overnight. To overcome thisproblem, many approaches have been tried but with only partial success.It has been found that where decolorized oil is kept under relativelycool conditions, such as 140 F. when compared to 212 F, the oil does notdarken as rapidly. It has also been determined that decolorized oil doesnot darken as rapidly if it is not stored in iron storage vessels.Comparative tests have shown that when stored in glass, the decolorizedoil has a tendency to retain a bleached color more readily. Decolorizedoil has also been stored under nitrogen, rather than in contact withair, with a certain amount of success. Moisture content has also beencontrolled with the result that partial stabilization is apparent.

Such known methods, however, have not produced adequate stabilizationagainst color reversion to the point that the problem no longer ispresent.

It is, therefore, an object of the present invention to treatdecolorized tallow in such a manner as to substantially overcome colorreversion.

Other objects, not specifically set forth, will become apparent from thefollowing detailed description.

Generally, the present invention comprises the addition of quantities ofhexamethylenetetramine to decolorized tallow prior to the storage of thetallow. It has been found that small percentages ofhexamethylenetetramine added to propane-decolorized tallow, while thetallow is still in a decolorized state, substantially prevents the colorreversion which normally occurs when propanedecolorized tallow is storedunder elevated temperatures. It is known that elevated temperaturespromote color reversion, but due to the need for elevated temperaturesduring storage it has been found necessary to take steps to reduce colorreversion while maintaining such conditions. The use of smallpercentages of hexamethylenetetramine as an additive topropane-decolorized tallow not only reduces the color reversionproperties of the decolorized tallow under normal conditions, but alsoreduces the color reversion properties of the decolorized nited StatesPatent tallow under commonly-practiced storage conditions whereinelevated temperatures are utilized.

The following examples are illustrative of the present invention and arenot intended to be considered as limiting thereto:

Samples of grams each of propane-decolorized tallow were stored in openjars at elevated temperatures. Color readings were taken daily based onthe F. A. C. color index which is well known in the art. Separatesamples were treated with hexamethylenetetramine in amounts ranging from0.01% additive to 1% additive. A control sample was left untreated forcomparative purposes. The following comparative table Was formed from F.A. C. readings taken on each sample over extended time intervals.

F. A. 0. Colors Additive, percent by weight Days at; F.

l 0 5 I 10 I 15 Control (No additive) 7 11 I 13 i 17 0.01%Hexarnethylenetctramine 7 9 11 I 13 Control (N o additive) 7 l1 13 j 170.1% Hexamethylenetctraminc 7 7 S) i 11 Days at 212 F.

Control (N 0 additive) 5 21 25 1% Hexamethylenotetramine. 5 17 21 In theabove examples the changes in color were determined by use of the F. A.C. color index. This index is based on an arbitrary system of colorstandards which makes use of various colored solutions of inorganicsalts. The diiferent salt solutions are sealed in vials and 26 suchvials are used to make up the index. Each is given an odd number and theentire set is divided into five series. Light-colored fats are graded bythe colors included in the first series which contains numbers 1 to 9,inclusive. The second series contains numbers 11, 11A, 11B, and 11Cwhich are used for very yellow fats. Numbers 13 to 19 make up the thirdseries and are used in conjunction with dark, reddish fats. The fourthseries contains numbers 21 to 29 for greenish fats and the fifth series,for very dark fats, is made up of numbers 31 to 45. This system iswidely used in the art.

As can readily be seen from the above comparative results, the use ofthe color reversion inhibitor of the present invention substantiallyreduces color reversion in decolorized tallow. Such results are highlydesirable from the standpoint of producing a stabilized product. Theamounts of agent added may differ substantially depending on the storagetime contemplated. However, there are practical limits as to the amountof additive used. This practical range exists from 0.01% by weightadditive to 1% by weight additive. it is considered uneconomical to goabove the 1% limit while it is not believed that suflicient additivewould be present if less than 0.81% were utilized.

Along with the use of the additives of the present invention otherwell-kuown practices may be followed. Small percentages of citric acidmay be added where the fat is to be stored in contact with carbon steel.Citric acid is well-known as a metal scavenger and, as such, helps inmaintaining fat in a decolorized state under such conditions. Inaddition to the additives of the present invention, iron storagevessels, glass storage vessels, storage under nitrogen or moisturecontrol methods may be used.

These different methods may be used collectively or in any "2,188,256 ra ,7 I v combination desirable along with one of the additives of thepresent invention.

Obviously, many modifications and variations of the invention ashereinbefore set forth may be made ithout departing from the spirit andscope thereof, and therefore only such limitations shouldbe imposed asare indicated in the appended claims.

We claim: j

1. In the treatment of tallow the method of inhibiting color reversionwhich comprises: decolorizing said tallow with propane and immediatelythereafter adding to said tallow relatively small quantities ofhexamethylenetetramine.

2. In the treatment of tallow the method of inhibiting color reversionwhich comprises: decolorizing said tallow with propane and immediatelythereafter adding to said f F 4 tallow at least 0.01% by weight ofhexamethylenetetramine.

3. In the treatment of tallow the method of inhibiting color reversionwhich comprises: decolorizing said tallow with propane and immediatelythereafter adding to said tallow quantities ranging from 0.01% to 1.0%by Weight of hexamethylenetetramine.

References Cited in the file of this patent UNITED STATES PATENTS1,542,438 Divine June 16, 1925 1,938,999 Cox Dec. 12, 1933 2,029,506Reed Feb. 4, 1936 2,154,341 Martin Apr. 11, 1939 2,456,937 Gyorgy -4Dec. 21, 1948 2,680,122 Black June 1, 1954

1. IN THE TREATMENT OF TALLOW THE METHOD OF INHIBITING COLOR REVERSIONWHICH COMPRISES: DECOLORIZING SAID TALLOW WITH PROPANE AND IMMEDIATELYTHEREAFTER ADDING TO SAID TALLOW RELATIVELY SMALL QUANTITIES OFHEXAMETHYLENETETRAMINE.